Friction element for disk brakes



Oct. 20, 1953 J. C. Mc E FRICTION ELEMENT FOR DISK BRAKES Filed May 51,1950 o m fi VA/ f? 1 1 my 1 r lllI/ll/I! AT TORNE Y Patented Oct. 20,1953 UNITED STATES ATENT OFFICE.

2,656,020 rmcrron ELEMENT FOR DISK BRAKES,

Application May 31, 1950, Serial No. 165,303

(c1. 1ss-240) 3 Claims.

This invention relates to friction elements and more particularly tothose employed as stators in disc brakes.

The prime object of the present invention is to provide an improvedfriction element of the above type provided with friction shoes whichmay be replaced with ease and which will not warp or crack with heavyprolonged use.

Other objects and advantages will become apparent from the followingmore detailed description of the invention.

In the accompanying drawing Fig. l is a face view of a segment of anannular friction element embodying the invention; Fig. 2 is acrosssectional view taken along the line 2-2 in Fig. 1; Fig. 3 is across-sectional view taken along the line 3-3 in Fig. 1; and Fig. l is aperspective view of a backing plate comprised in the structure shown inthe preceding figures.

Description Referring to the drawing, the friction element embodying thinvention comprises an annular body I and is adapted particularly foruse as a non-rotatable braking element of a disc brake by provision of aplurality of aligned, circumferentially spaced-apart, rectangularopenings 4 to accommodate the usual non-rotatable torque bars (notshown) on which the body i is thereby adapted to be slidably mounted. Bysliding movement of the body I on the usual torque bars, brakingengagement between the non-rotatable friction element and a rotatablefriction element or elements (not shown) may be effected in thewell-known manner. Braking torque forces resulting from such brakingengagement will be transmitted to the non-rotatable torque bars (notshown) by respective shoulders formed by wear pads 6 welded torespective edges of openings 4. The pads ii afford a greater bearingsurface for abutment with the torque bars than the thickness of the bodyat openings 4 affords and protects the edges of the openings 4 fromexcessive wear. Termination of braking engagement is effected byslidable movement of body I on the torque bars (not shown) in adirection away from the rotatable braking element or elements (notshown).

The body I carries a plurality of circumferentially spaced apartremovable brake shoe members 8. Each brake shoe member 8 comprises abacking plate 9 of sheet steel which may be formed by stamping, forexample, and upon one side of which is cast a brake shoe It forfrictional interengagement with corresponding shoes on the rotatablebraking element (not shown), the opposite side of said member being flatfor engagement with a flat surface I5 of body I. Each of the backingplates 9, is provided with a shoe carrying portion having a rectangularshaped slot II midway between the ends of the plate and open at theinner edge of the plate (as mounted on body I), and a plurality ofspaced apart openings I2 at opposite sides of said slot which openingsare elongated in the direction of the radius of the body I, as saidplate is mounted on said body. The portions or webs I3 provided betweenthe openings l2 at eachside of slots I I are pressed out of the plane ofthe surrounding portion of the plate 9 in a direction away from the sideof the plate adapted to engage the body I, a distan-2e exceeding thethickness of said plate so as to provide at the body side of each web arecess into and through which molten metal may flow via and betweenopening I2 during casting of the shoe Ill onto said plate, which shoeupon cooling, provides a flat surface of backing plate and shoe formounting on the smooth plane surface I5 of the annular body I. The websI3 thus being surrounded by metal integral with the metal at the brakingside of the plate acts to securely hold the brake shoe to. said plate.,cast shoe Iii within the groove II is formed, pref- In the back of eacherably during casting, a rectangular slot is to accommodate a torquetransmitting lug [9 at- .tached by means of such as welds 20 to the faceI5 at the inner peripheral edge of body I equidistant from adjacentopenings 4. Each of the lugs I9 is preferably rectangular in shape topro- .vide two opposite shoulders extending parallel to a radius of thebody I for free sliding engage- .ment with corresponding shouldersformed by the slot I8 in the shoe It).

A slight clearance between torque lugs I9 and shoes It exists to allowfor thermal expansion of such shoes during heavy prolonged brakeapplications.

Each of the brake shoe members 8 is held in place radially of theannular body I by a retaining pin 24 rigidly attached to said body, bysuch as a weld 25, in radial alignment with one of the lugs II). Anopening 25 in a projecting portion 28 of each backing plate 9 isprovided to accommodate the pin 24. The length of the shoe carryingportion of the backing plate is less than the distance between adjacentopenings 4 so that in assembly of the shoe member 8 to the body I, whenthe friction element is in position in a brake, each member may beslipped radially inward of said body between the adjacent respectivetorque bars (not shown) extending through the openings 4 into place onthe lugs I9, and the respective opening 26 in the backing plates 9 maythen be brought into registry with and slipped over the respectiveretaining pin 24. All shoe members 8, once positioned as above, are thenheld so positioned in contact with the surface I5 of the body I by anannular retaining ring 36 removably secured by means such as cap screws3I to said body. The annular retaining ring 3!] when in place isdisposed adjacent to the outer peripheral edge of the annular body I inengagement with the radially outward projecting ends of each portion 28of the backing plates 9 and covering projecting ends of the retainingpins 24; sockets being provided in said ring at the 10- cations of pins24 to accommodate the ends of same and aid in locating the ring prior toinsertion of cap screws 3|. The projecting ends of each of the portions28 of the backing plates 9 are provided with slots 35 one at either sideof the respective pin 24 and open to the outer edge of the plate throughwhich the cap screws 3! may extend in securing the ring 89 to the bodyI. The shoe members 8 easily may be removed from the body I, forreplacement, for example, by removal of the cap screws 3! and theretaining ring 30, after which said members may be freed from the pins24 and slipped radially outward from the lug I9 between openings l.

It should be pointed out that during employment of the assembledfriction element in a disc brake, when the shoes Ill are in frictionalbraking engagement with other shoes in such brake, torque forcesresultant from such engagement is transmitted substantially directlyfrom the shoes to the body I by way of the lugs I 9 in which they are inengagement. The backing plates 9 are subjected to little if any suchtorque forces and act substantially exclusively as mediums through whichthe shoes ID are attached to the body I for carriage thereby.

Summary It will now be seen that I have provided an improved frictionelement particularly adapted for use as a non-rotatable friction brakingelement in a disc brake for railway use, which friction elementcomprises removable friction shoes which are easily replaceable andwhich will not crack or warp with excessiv prolonged use.

Having now described my invention, what I claim as new and desire tosecure by Letters Patent, is:

1. In a disc brake or the like, a friction element comprising incombination, a body having a mounting face, a torque transmitting lugattached to said body and projecting from said face, a retaining pinattached to said body and projecting from said face, a backing platehaving an opening receiving said retaining pin, a friction shoe castonto said backing plate and having a socket in engagement with said luand slidable thereon in the direction of said pin, and removable meansholding said backing plate on said pin.

2. In a disc brake or the like, a friction element comprising incombination, an annular body having a mounting face, a plurality ofcircumferentially spaced apart torque transmitting lugs attached to saidbody and projecting from said face, an equal number of circumferentiallyspaced apart retaining pins attached to said body and projecting fromsaid face in radial alignment with said lugs, a plurality of backingplates each having an opening receiving a respective one of said pins, aplurality of friction shoes each cast onto a respective one of saidbacking plates and having a socket open at a side opposite said pin anddisposed in radially slidable engagement with a respectiv one of saidlugs, and a retaining ring removably attached to said body holding saidbacking plates in proximity of said face.

3. In a disc brake or the like, a friction element comprising incombination, a body having an annular mounting face and a plurality ofcircumferentially spaced apart axially extending torque baraccommodating openings adjacent the outer peripheral edge of said face,a plurality of circumferentially spaced apart torque transmitting lugsat the inner peripheral edge of said body spaced equidistant from saidopenings and projecting from said face, a plurality of backing platesremovably secured in contact with said face and each having an elongatedshoe mounting portion disposed at right angles to the radius of saidbody and of lesser longitudinal dimension than the distance betweenadjacent edges of said openings, and a plurality of friction shoes eachcast onto a respective one of said backing plates and each having asocket abutting a respective one of said lugs and being slidable thereonradially outward of said body.

JOSEPH C. McCUNE.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 787,079 Collier Apr. 11, 1905 1,054,974 Marquart Mar. 4, 19131,867,348 Blume July 12, 1932' 2,451,326 Eksergian et a1. Oct. 12, 19482,451,329 Gaenssle Oct. 12, 1948 2,498,501 Newell Feb. 21, 1950 FOREIGNPATENTS Number Country Date 171,503 Great Britain Nov. 24, 1921

